What is A Rectifier Transformer?

A rectifier transformer is a transformer specially designed for rectification system, its principle is the same as that of an ordinary transformer, it is a kind of equipment for converting AC voltage according to the principle of electromagnetic induction.

The transformer generally has primary and secondary windings that are independent of each other, and these two windings share an iron core. When the primary winding of the transformer is connected to the AC power supply, an alternating current flows through the winding to produce a magnetic potential, so there is an alternating magnetic flux in the closed core. The primary winding cuts the magnetic line of force, and an alternating current of the same frequency is induced in the secondary winding. The turns ratio of the primary and secondary windings of a transformer is equal to the voltage ratio.

The Difference Between Rectifier Transformers and Power Transformers

A transformer used to supply power to a rectifier is called a rectifier transformer. Rectifier transformers and power transformers are similar in operation (Faraday's law of electromagnetic induction), structure (consisting of two or more windings wound on a common core), and appearance (both are stationary electrical devices). There are, however, major differences between the two.

1. Power transformers have only three sinusoidal pulses in one cycle. Rectifier transformers can have up to 6 or 12 pulses in one cycle (i.e., equivalent number of phases).

2.Power transformers usually match high and low voltage levels with grid voltage levels, while rectifier transformers only match line side voltages with grid voltage levels, while valve side voltages can be based on load requirements and rectification methods.

3. Rectifier transformer needs commutation impedance calculation.

4.The additional losses due to harmonics of the rectifier transformer cannot be ignored. Therefore, the amount of copper and the amount of silicon steel sheets used in the manufacture of rectifier transformers with the same power level is much higher.

Thus, the forging plant to the thyristor IF inverter power supply transformer with power transformer replacement is not appropriate. Rectifier transformers must be used whenever a load such as a thyristor IF inverter is present.

Rectifier transformers are used in the electrochemical industry, which is the industry with the most applications for rectifiers, for the electrolysis of non-ferrous metal compounds to produce aluminum, magnesium, copper, and other metals, for the electrolysis of table salt, to produce Chlor-alkali, and for the electrolysis of water to produce hydrogen and oxygen.

The most important feature of rectifier transformers is that the secondary current is not sinusoidal AC anymore. Due to the uni-directional on-commutation feature of the subsequent rectifier elements, each phase no longer flows simultaneously, but the load current is soft current conductive, and the unidirectional pulsating current is changed to DC by the filter device.

The secondary voltage and current of the rectifier transformer are not only related to the capacity of the connection group, such as the commonly used three-phase bridge rectifier line, double inverse rectifier line with the balanced reactor but for the same DC output voltage and current of the rectifier transformer required secondary voltage and current are different.

Therefore, the parameter calculation of the rectifier transformer is based on the premise of the rectifier line, and generally, the parameter calculation is extrapolated from the secondary side to the primary side. 

The above information is provided by the rectifier transformer supplier.